As you might expect jTDS is not 100% documented, but there is a lot of
information lying around and we are currently working on organizing all
this information into something that's easy to use. For now, there's the
FAQ, the javadoc-generated HTML, the (reverse engineered) TDS 7.0 protocol
specification, various benchmark results and a feature matrix. If you
are interested in helping us or have any kind of related documentation,
please let us know.

Here are the links. For jTDS users:

The Frequently Asked Questions page. This is
where you'll find the answers to the most common questions but also
detailed information on using jTDS. Check it out first if you never
used jTDS before.

The jTDS feature matrix. The fastest way
to check whether jTDS has everything you need or not.

Benchmark results. We have benchmarked jTDS against some well-known
commercial drivers and of course the Microsoft driver and the JDBC-ODBC
bridge, using two different benchmarks, provided by two leading commercial
driver vendors: i-net
software and JNetDirect.
Here are the results of the i-net test: BenchTest 2.1 for
MS SQL Server. The JNetDirect license precludes publication of performance test results.
However, jTDS is generally faster than all other drivers.

Information about jTDS ResultSet
support. What ResultSet types are supported and some
guidelines on how to ensure correct behavior.

For developers and those interested in finding out more about jTDS and/or
SQL Server:

jTDS API documentation (javadoc-generated). Please
note that this might be somewhat out of date, it's pretty hard remembering
to update it. If you want to make sure you get the last version, go
to the download page and get the jTDS source package. It contains the
last javadoc-generated documentation.

Some TDS 7.0 documentation. Incomplete (since
it's obtained by reverse-engineering the data stream between SQL Server
and jTDS or various other clients) but it contains enough new information
to make it interesting and useful. Be sure to also check out the documentation
provided by the FreeTDS project, as it pretty much complements the stuff
we have.

Documentation on SQL Server
API server cursors (i.e. the undocumented stored procedures used
in the background by all the Microsoft client implementations to handle
cursors). This is some pretty new stuff, assembled from scratch by the
jTDS Project, but it's quite complete.

Interested in joining the project? Here's
a short document describing how you can become a project member. You
don't have to do anything you don't want to, just have fun writing code,
tests, documentation, helping out people or reverse engineer M$'s well
kept secrets.